U.S. patent application number 14/106570 was filed with the patent office on 2015-02-19 for shift control method and system of hybrid vehicle.
This patent application is currently assigned to Hyundai Motor Company. The applicant listed for this patent is Hyundai Motor Company. Invention is credited to Myunggyu Kim, Yeonho Kim, Sang Mo Ryu.
Application Number | 20150051765 14/106570 |
Document ID | / |
Family ID | 52430156 |
Filed Date | 2015-02-19 |
United States Patent
Application |
20150051765 |
Kind Code |
A1 |
Ryu; Sang Mo ; et
al. |
February 19, 2015 |
SHIFT CONTROL METHOD AND SYSTEM OF HYBRID VEHICLE
Abstract
A shift control method and system of a hybrid vehicle that
prevent engine clutch slip occurring when a transfer torque of
engine clutch is greater than an allowable transfer torque under
unfavorable driving conditions by controlling a shifting time, may
include, (a) detecting an engine torque. (b) determining an input
torque of an engine clutch based on the engine torque. (c)
comparing the determined input torque and a predetermined allowable
transfer torque of the engine clutch. (d) increasing a present
shifting time by a predetermined value when the determined input
torque is greater than the allowable transfer torque and applying
the increased shifting time.
Inventors: |
Ryu; Sang Mo; (Busan,
KR) ; Kim; Myunggyu; (Seoul, KR) ; Kim;
Yeonho; (Suwon-si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hyundai Motor Company |
Seoul |
|
KR |
|
|
Assignee: |
Hyundai Motor Company
Seoul
KR
|
Family ID: |
52430156 |
Appl. No.: |
14/106570 |
Filed: |
December 13, 2013 |
Current U.S.
Class: |
701/22 ;
180/65.27; 903/902 |
Current CPC
Class: |
B60W 10/02 20130101;
B60W 2710/026 20130101; B60W 2510/0695 20130101; B60W 20/40
20130101; B60W 30/19 20130101; B60W 2510/0657 20130101; B60W 20/30
20130101; B60W 2510/0652 20130101; B60W 10/06 20130101; Y10S
903/902 20130101; B60W 2710/023 20130101; B60W 20/10 20130101 |
Class at
Publication: |
701/22 ;
180/65.27; 903/902 |
International
Class: |
B60W 20/00 20060101
B60W020/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 13, 2013 |
KR |
10-2013-0095813 |
Claims
1. A shift control method of a hybrid vehicle comprising: (a)
detecting an engine torque; (b) determining an input torque of an
engine clutch based on the engine torque; (c) comparing the
determined input torque and a predetermined allowable transfer
torque of the engine clutch; and (d) increasing a present shifting
time by a predetermined value when the determined input torque is
greater than the allowable transfer torque, and applying the
increased shifting time.
2. The method of claim 1, further comprising: (e) comparing the
predetermined allowable transfer torque and the input torque which
is recalculated after applying the shifting time increased by the
predetermined value, wherein the steps (d) and (e) are repeatedly
performed when the input torque which is recalculated after
applying the shifting time increased by the predetermined value is
greater than the predetermined allowable transfer torque.
3. The method of claim 1, wherein the input torque is determined by
the equation T.sub.in=T.sub.E*(I.sub.input*a), and wherein T.sub.in
is the input torque, T.sub.E is the engine torque, I.sub.input is
input inertia or rotational inertia of an engine, and a is angular
acceleration.
4. The method of claim 1, wherein the input torque is determined by
multiplying the predetermined allowable transfer torque by a
predetermined safety coefficient.
5. The method of claim 1, wherein the shifting time is increased by
a predetermined ratio.
6. A shift control system of a hybrid vehicle comprising: a
dry-type engine clutch configured to control transmission of power
between an engine and a motor; an engine control unit (ECU)
configured to control the engine; a motor control unit (MCU)
configured to control the motor; a transmission control unit (TCU)
configured to control a transmission; a hybrid control unit (HCU)
configured to control an entire operation of the hybrid vehicle;
and a shifting controller configured to increase a shifting time by
a predetermined value when an input torque of the engine clutch
determined on the basis of engine torque, input inertia, and
angular acceleration is greater than a predetermined allowable
transfer torque of the engine clutch, wherein the shifting
controller is operated by a predetermined program for performing
the method of claim 1.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority to Korean Patent
Application No. 10-2013-0095813 filed on Aug. 13, 2013, the entire
contents of which is incorporated herein for all purposes by this
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a shift control method and
system of a hybrid vehicle. More particularly, the present
invention relates to a shift control method and system of a hybrid
vehicle that prevent engine clutch slip from occurring when a
transfer torque of engine clutch is greater than an allowable
transfer torque under unfavorable driving conditions by controlling
a shifting time.
[0004] 2. Description of Related Art
[0005] As is generally known in the art, a hybrid vehicle uses an
internal combustion engine and a battery power supply together.
That is, the hybrid vehicle efficiently combines power of the
internal combustion engine and power of a driving motor for
use.
[0006] As illustrated in FIG. 1, the hybrid vehicle may include,
for example, an engine 10, a driving motor 20, an engine clutch 30
for intermitting between power between the engine 10 and the
driving motor 20, a transmission 40, a differential gear device 50,
a battery 60, an integrated starter-generator 70 for starting the
engine 10 or generating electricity by rotational force of the
engine 10, and vehicle wheels 80.
[0007] Furthermore, the hybrid vehicle may include a hybrid control
unit (HCU) 200 for controlling an entire operation of the hybrid
vehicle. an engine control unit (ECU) 110 for controlling an
operation of the engine 10. a motor control unit (MCU) 120 for
controlling an operation of the driving motor 20. a transmission
control unit (TCU) 140 for controlling an operation of the
transmission 40. a battery control unit (BCU) 160 for controlling
and managing the battery 60.
[0008] The battery control unit 160 may be called a battery
management system (BMS). The integrated starter-generator 70 may be
called an integrated starter & generator (ISG), or a hybrid
starter & generator (HSG).
[0009] The hybrid vehicle may be driven in a driving mode such as
an electric vehicle (EV) mode which is a true electric vehicle mode
using only power of the driving motor 20, a hybrid vehicle (HEV)
mode which uses rotational force of the engine 10 as main power and
uses rotational force of the driving motor 20 as auxiliary power,
and a regenerative braking (RB) mode for collecting braking and
inertial energy during driving by braking or inertia of the vehicle
through electric generation of the driving motor 20 to charge the
battery 60.
[0010] The hybrid vehicle may use a dry-type engine clutch, and the
dry-type engine clutch should be maintained fully closed condition
while shifting. Therefore, an allowable transfer torque of the
dry-type engine clutch may be determined by a motor, a rotational
inertia of the engine, an angular acceleration, and an engine
torque.
[0011] However, engine clutch slip may occur because a transfer
torque is greater than an allowable transfer torque when the hybrid
vehicle is operated under unfavorable driving conditions. For
example, the engine clutch slip may occur when the hybrid vehicle
is operated at an extremely low temperature or the hybrid vehicle
shifts according to an additional torque of the engine.
[0012] That is, when the hybrid vehicle is operated under
unfavorable conditions, the engine clutch slip may occur due to a
difference of rotational inertia between the motor and the engine
that is generated when the transfer torque is greater than the
allowable transfer torque during shifting. when such an engine
clutch slip occurs, the hybrid vehicle is negatively influenced
with regard to shifting safety, vehicle vibration, and fuel
consumption.
[0013] In order to prevent the aforementioned problem, the
allowable transfer torque of the engine clutch is increased, but
the size of the engine clutch and a secure space for installing it
need to increase.
[0014] The information disclosed in this Background of the
Invention section is only for enhancement of understanding of the
general background of the invention and should not be taken as an
acknowledgement or any form of suggestion that this information
forms the prior art already known to a person skilled in the
art.
BRIEF SUMMARY
[0015] Various aspects of the present invention are directed to
providing a shift control method and system of a hybrid vehicle
having advantages of preventing engine clutch slip generated when
transfer torque of an engine clutch is greater than an allowable
transfer torque according to unfavorable driving conditions by
controlling a shifting time.
[0016] In an aspect of the present invention, a shift control
method of a hybrid vehicle may include (a) detecting an engine
torque, (b) determining an input torque of an engine clutch based
on the engine torque, (c) comparing the determined input torque and
a predetermined allowable transfer torque of the engine clutch, and
(d) increasing a present shifting time by a predetermined value
when the determined input torque is greater than the allowable
transfer torque, and applying the increased shifting time.
[0017] The method may further include (e) comparing the
predetermined allowable transfer torque and the input torque which
is recalculated after applying the shifting time increased by the
predetermined value, wherein the steps (d) and (e) are repeatedly
performed when the input torque which is recalculated after
applying the shifting time increased by the predetermined value is
greater than the predetermined allowable transfer torque.
[0018] The input torque is determined by the equation
T.sub.in=T.sub.E*(I.sub.input*a), and T.sub.in is the input torque,
T.sub.E is the engine torque, I.sub.input is input inertia or
rotational inertia of an engine, and a is angular acceleration.
[0019] The input torque is determined by multiplying the
predetermined allowable transfer torque by a predetermined safety
coefficient.
[0020] The shifting time is increased by a predetermined ratio.
[0021] In another aspect of the present invention, a shift control
system of a hybrid vehicle may include a dry-type engine clutch
configured to control transmission of power between an engine and a
motor, an engine control unit (ECU) configured to control the
engine, a motor control unit (MCU) configured to control the motor,
a transmission control unit (TCU) configured to control a
transmission, a hybrid control unit (HCU) configured to control an
entire operation of the hybrid vehicle, and a shifting controller
configured to increase a shifting time by a predetermined value
when an input torque of the engine clutch determined on the basis
of engine torque, input inertia, and angular acceleration is
greater than a predetermined allowable transfer torque of the
engine clutch, wherein the shifting controller is operated by a
predetermined program for performing the forgoing method.
[0022] As described above, according to an exemplary embodiment of
the present invention, the present invention prevents engine clutch
slip occurring when a transfer torque of the engine clutch is
greater than an allowable transfer torque under unfavorable driving
conditions by controlling a shifting time, so that shifting safety
and fuel consumption of the hybrid vehicle are improved.
[0023] The methods and apparatuses of the present invention have
other features and advantages which will be apparent from or are
set forth in more detail in the accompanying drawings, which are
incorporated herein, and the following Detailed Description, which
together serve to explain certain principles of the present
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is a schematic block diagram of a general hybrid
vehicle.
[0025] FIG. 2 is a schematic block diagram of a shift control
system of a hybrid vehicle according to an exemplary embodiment of
the present invention.
[0026] FIG. 3 is a flowchart showing a shift control method of a
hybrid vehicle according to an exemplary embodiment of the present
invention.
[0027] FIG. 4 is a graph for describing an operation of a shift
control method and system of a hybrid vehicle according to an
exemplary embodiment of the present invention.
[0028] It should be understood that the appended drawings are not
necessarily to scale, presenting a somewhat simplified
representation of various features illustrative of the basic
principles of the invention. The specific design features of the
present invention as disclosed herein, including, for example,
specific dimensions, orientations, locations, and shapes will be
determined in part by the particular intended application and use
environment.
[0029] In the figures, reference numbers refer to the same or
equivalent parts of the present invention throughout the several
figures the drawing.
DETAILED DESCRIPTION
[0030] Reference will now be made in detail to various embodiments
of the present invention(s), examples of which are illustrated in
the accompanying drawings and described below. While the
invention(s) will be described in conjunction with exemplary
embodiments, it will be understood that the present description is
not intended to limit the invention(s) to those exemplary
embodiments. On the contrary, the invention(s) is/are intended to
cover not only the exemplary embodiments, but also various
alternatives, modifications, equivalents and other embodiments,
which may be included within the spirit and scope of the invention
as defined by the appended claims.
[0031] The present invention will be described more fully
hereinafter with reference to the accompanying drawings, in which
exemplary embodiments of the invention are shown. As those skilled
in the art would realize, the described embodiments may be modified
in various different ways, all without departing from the spirit or
scope of the present invention.
[0032] Through the present specification, unless explicitly
described otherwise, "including" any components will be understood
to imply the inclusion of other components rather that the
exclusion of any other components.
[0033] Like reference numerals are given to like components
throughout the specification.
[0034] FIG. 2 is a schematic block diagram of a shift control
system of a hybrid vehicle according to an exemplary embodiment of
the present invention.
[0035] The shift control system of the hybrid vehicle according to
an exemplary embodiment of the present invention controls a
shifting time when an input torque of an engine clutch of the
hybrid vehicle is greater than a predetermined allowable transfer
torque.
[0036] The shift control system of the hybrid vehicle according to
an exemplary embodiment of the present invention may include an
engine clutch 30 for controlling a transmission of power between an
engine 10 and a motor 20, an engine control unit (ECU) 110 for
controlling the engine 10, a motor control unit (MCU) 120 for
controlling the motor 20, a transmission control unit (TCU) 140 for
controlling a transmission 40, and a controller 300 for increasing
a shifting time by a predetermined value when an input torque of
the engine clutch 30 calculated on the basis of an engine torque,
an input inertia, and an angular acceleration is greater than a
predetermined allowable transfer torque of the engine clutch
30.
[0037] The engine 10, the motor 20, the transmission 40, the engine
control unit 110, motor control unit 120, and transmission control
unit 140 may be installed in a general hybrid vehicle as shown in
FIG. 1.
[0038] The engine clutch 30 according to an exemplary embodiment of
the present invention may preferably be a dry-type engine
clutch.
[0039] The controller 300 may be implemented with one or more
microprocessors operated by a predetermined program or hardware
including the microprocessor, and the predetermined program
includes a series of commands for performing a shifting control
method of a hybrid vehicle according to an exemplary embodiment of
the present invention to be described below.
[0040] The controller 300 according to an exemplary embodiment of
the present invention may preferably play a role of a hybrid
control unit (HCU) 200 as shown in FIG. 1. That is, the controller
300 may include the hybrid control unit 200 or be included in the
hybrid control unit 200.
[0041] Hereinafter, the shifting control method of the vehicle
according to an exemplary embodiment of the present invention will
be described in detail with reference to the accompanying
drawings.
[0042] FIG. 3 is a flowchart showing a shift control method of a
hybrid vehicle according to an exemplary embodiment of the present
invention.
[0043] As shown in FIG. 3, the controller 300 detects an engine
torque while the hybrid vehicle operates at step S110. For example,
the controller 300 may use the engine torque detected by the engine
control unit ECU 110. The fact that the engine control unit ECU 110
detects the engine torque is publicly known, so a detailed
description thereof will be omitted in the present
specification.
[0044] If the engine torque is detected, the controller 300
calculates the input torque of the engine clutch 30 at step S120.
The controller 300 may use the engine torque while calculating the
input torque. For example, the controller 300 may calculate the
input torque by the equation below.
T.sub.in=T.sub.E*(I.sub.input*a)
[0045] (T.sub.in, input torque, T.sub.E, engine torque,
I.sub.input, input inertia or rotational inertia of engine, a,
angular acceleration)
[0046] The controller 300 may calculate the input torque according
to the equation above, but it should be understood that the present
invention is not limited thereto. The controller 300 may calculate
the input torque by any method which is well known in the art.
Also, the controller 300 may calculate the input torque by
multiplying an allowable transfer torque of the engine clutch 30
which will be described later by a predetermined safety coefficient
(for example, 0.8).
[0047] The input inertia and the angular acceleration of the engine
clutch 30 in the equation above are calculated or detected in the
art, so a detailed description thereof will be omitted in the
present specification.
[0048] The input inertia of the engine clutch 30 may be the
rotational inertia of the engine.
[0049] If the input torque is calculated, the controller 300
compares the input torque and a predetermined allowable transfer
torque at step S130.
[0050] The allowable transfer torque may be a predetermined value
found by using an available value of the engine clutch 30.
[0051] After comparing the input torque and the allowable transfer
torque in step S130, if when the input torque is greater than the
allowable transfer torque, the controller 300 increases a present
shifting time (for example, by 0.3 seconds) at step S140.
[0052] For example, if the input torque is greater than the
allowable transfer torque, the controller 300 may increase the
present shifting time of 0.3 seconds to 0.7 seconds as shown in
FIG. 4.
[0053] In the past, the shifting time was set as the short 0.3
seconds as shown in FIG. 4 (A) when the input torque was greater
than the allowable transfer torque, so a slip of the engine clutch
30 occurred because the engine speed and/or motor speed variation
was 3000 rpm/s. That is, the shifting time was maintained short
when the input torque was greater than the allowable transfer
torque in the past. Therefore, the engine speed did not follow
deceleration of the motor speed due to shifting caused by the
difference of rotational inertia of the engine 10 and the motor 20,
so the slip of the engine clutch 30 occurred.
[0054] On the contrary, according to an exemplary embodiment of the
present invention, the controller 300 may increase the shifting
time by a predetermined value, for example to 0.7 seconds as shown
in FIG. 4 (B) when the input torque is greater than the allowable
transfer torque, so that the controller 300 may prevent the slip of
the engine clutch 30 that occurred in the past.
[0055] That is, if when the shifting time is lengthened to 0.7
seconds when the input torque is greater than the allowable
transfer torque, the engine speed and/or motor speed variation is
1740 rpm/s and the recalculated input torque is decreased
accordingly (S150), so that the slip of the engine clutch 30 does
not occur because the engine speed is almost equal to the motor
speed.
[0056] In case the input torque is greater than the allowable
transfer torque as described above occurs when the hybrid vehicle
is operated under unfavorable driving conditions, for example at
less than -40 degrees C., the controller 300 may perform the method
according to an exemplary embodiment of the present invention only
under predetermined driving conditions, but it should be understood
that the present invention is not limited thereto.
[0057] If the input torque recalculated in step S150 based on the
increased shifting time in step S140 is still greater than the
allowable transfer torque (S160), the controller 300 repeatedly
performs steps after S140 to try to decrease the input torque by
increasing the shifting time.
[0058] The shifting time is increased by a predetermined ratio in
step S140, for example, from 100 to 250 percent of the present
shifting time.
[0059] If the input torque is less than or equal to the allowable
transfer torque in steps S130 and/or S160, the controller 300
applies each corresponding shifting time to the shifting in step
S170.
[0060] Thereby, according to an exemplary embodiment of the present
invention, the problem of having engine clutch slip occur can be
solved without increasing the size of the engine clutch by
controlling the shifting time.
[0061] For convenience in explanation and accurate definition in
the appended claims, the terms "upper", "lower", "inner" and
"outer" are used to describe features of the exemplary embodiments
with reference to the positions of such features as displayed in
the figures.
[0062] The foregoing descriptions of specific exemplary embodiments
of the present invention have been presented for purposes of
illustration and description. They are not intended to be
exhaustive or to limit the invention to the precise forms
disclosed, and obviously many modifications and variations are
possible in light of the above teachings. They are not intended to
be exhaustive or to limit the invention to the precise forms
disclosed, and obviously many modifications and variations are
possible in light of the above teachings as well as various
alternatives and modifications thereof. It is intended that the
scope of the invention be defined by the Claims appended hereto and
their equivalents.
* * * * *